Remote control
R&S
®
QAR50
56
User Manual 1179.4992.02 ─ 02
●
LAN device name
defines the protocol and the instance number of a sub-instru-
ment;
●
INSTR
indicates the instrument resource class (optional)
Example:
●
Instrument has the IP address
192.1.2.3
; the valid resource string using VXI-11
protocol is:
TCPIP::192.1.2.3::INSTR
Identifying instruments in a network
If several instruments are connected to the network, each instrument has its own IP
address and associated resource string. The controller identifies these instruments by
the resource string.
VISA library
A VISA installation is a prerequisite for remote control using the LAN interface.
VISA is a standardized software interface library providing input and output functions to
communicate with instruments. High level programming platforms use VISA as an
intermediate abstraction layer.
The I/O channel (LAN or TCP/IP) is selected at initialization time by one of the follow-
ing:
●
The channel–specific address string ("VISA resource string")
●
An appropriately defined VISA alias (short name).
For more information about VISA, refer to the VISA user documentation.
VXI-11 protocol
The VXI-11 standard is based on the open network computing remote procedure call
(ONC RPC) protocol which in turn relies on TCP/IP at the network/transport layer. The
TCP/IP network protocol and the associated network services are preconfigured.
TCP/IP ensures connection-oriented communication, where the order of the
exchanged messages is adhered to and interrupted links are identified. With this proto-
col, messages cannot be lost.
SCPI compatibility
SCPI commands (standard commands for programmable instruments) are used for
remote control. The SCPI standard is based on standard IEEE 488.2 and aims at the
standardization of instrument-specific commands, error handling and the status regis-
ters. The tutorial "Automatic Measurement Control - A tutorial on SCPI and IEEE
488.2" from John M. Pieper (R&S order number 0002.3536.00) offers detailed informa-
tion on concepts and definitions of SCPI. The instrument supports the SCPI version
1999.
Commands that are not taken from the SCPI standard follow the SCPI syntax rules.
Remote control interface and protocol
